Added Sugar Adds Up to Heart Risk

On average, Americans get nearly 16% of their total dietary calories from sugars added to processed foods during manufacturing, researchers found.

by Michael Smith Michael Smith North American Correspondent, MedPage Today
April 20, 2010

Action Points

Explain to interested patients that extra sugar in many processed foods can add up to a significant heart health risk.

On average, Americans get nearly 16% of their total dietary calories from sugars added to processed foods during manufacturing, researchers found.

And a high intake of such sugars -- mainly sucrose from beets and cane and high fructose corn syrup -- is correlated with some key measures of dyslipidemia, according to Miriam Vos, MD, of Emory University in Atlanta, and colleagues.

Because dyslipidemia is a risk factor for cardiovascular disease, the findings support dietary guidelines aimed at reducing consumption of added sugars, Vos and colleagues said in the April 21 issue of the Journal of the American Medical Association.

The findings are not a surprise, according to Rachel Johnson, PhD, of the University of Vermont in Burlington. Johnson, a nutritionist, was the primary author of a statement on added sugars issued in August 2009 by the American Heart Association. (See Cut Back on Added Sugar, AHA Recommends)

"Among the nutrition science community, we're certainly not shocked by these findings," she told MedPage Today.

But the study "certainly adds strength to the evidence base around this issue," she added.

Indeed, Vos and colleagues noted in their paper, increased carbohydrate intake has been linked with dyslipidemia, but there has been no research on the links between added sugars and the condition.

To help fill the gap, they turned to the long-running National Health and Nutrition Examination Survey (NHANES) from 1999 through 2006. NHANES is a continuous survey of the US civilian, noninstitutionalized population that is designed to obtain nationally representative estimates on diet and health indicators.

The 6,113 respondents were divided into five groups based on the proportion of total energy intake from added sugars: less than 5% (serving as the reference group); 5% to less than 10%; 10% to less than 17.5%; 17.5% to less than 25%; and 25% or more.

The difference among the groups was striking: those in the lowest group consumed about three teaspoons of added sugar a day, compared with 46 teaspoons for the highest-consuming group, the researchers said.

As the intake of added sugars rose, participants were more likely to be younger, poorer, and non-Hispanic black; the linear trend was significant at P<0.001 for all three, Vos and colleagues found.

And people who consumed more added sugars obtained a lower percentage of their energy from total, polyunsaturated, monounsaturated, and saturated fats, as well as from protein, fiber, and cholesterol; the linear trend was significant at P<0.001 for all comparisons.

For men and women consuming less than 5% of total energy from added sugars, HDL-C averaged 58.7 milligrams per deciliter and triglycerides levels were 105 milligrams per deciliter.

For those in the next bracket -- 5% to less than 10% -- the numbers were 57.5 and 102, respectively.

Those who consumed still more -- 10% to less than 17.5% -- the numbers were 53.7 and 111, respectively.

In the second-highest bracket -- 17.5% to less than 25% -- HDL-C was 51.0 milligrams per deciliter and triglycerides were 113.

For those who got 25% or more of their energy from added sugars, HDL-C and triglycerides were 47.7 and 114 respectively.

The researchers found an interaction by sex in LDL-C levels, with only women having a significant trend (at P=0.047 for linear trend) toward higher levels associated with higher intakes of added sugars.

In a multivariate analysis, the researchers found that compared with the reference group, those with the highest consumption of added sugars were more than three times as likely to have LDL-C levels indicative of dyslipidemia -- less than 50 milligrams per deciliter for women and less than 40 for men. The trend was significant at P<0.001.

They were also 20% more likely to have high triglycerides (more than 150 milligrams per deciliter) and 60% more likely to have a high ratio of triglycerides to HDL-C (greater than 3.8), the researchers found.

Johnson said Americans have been focusing on removing fat from their diets, but haven't realized that added sugars can have the same ill effects for health.

"We've always thought of saturated fat in the diet as the culprit in terms of the dietary risk factors for heart disease," Johnson said. "Just lowering your fat and not thinking about what you replace it with is not putting you in a good place."

If people want to have sugar as part of their diet, Johnson said, one way is to make it part of a meal that is basically healthy -- brown sugar on oatmeal, for instance. "There are plenty of very delicious choices people can make," she said.

The researchers did not report external support for the study.

Vos reported that she is the author of and receives royalties from a book about childhood obesity. She is supported in part by a career award from the National Institute of Diabetes and Digestive and Kidney Diseases and from the Children's Digestive Health and Nutrition Foundation.

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